WHY??

I keep hearing about how you can charge stones by setting them out for a night under a full moon. I understand energy and how we all emit energy - and I have several charged stones.

But I just don't understand why the full moon charges them. They're from the earth - if anything you'd think that burying them for a while would work (getting back into the earth and whatnot). But the moon? Why?? Does anyone have articles on this? I can't find anything. . .